7. Project Abstract Pre-exposure prophylaxis (PrEP), a key biomedical HIV prevention strategy, can significantly reduce HIV incidence in real-world settings. However, introduction and global scale-up of PrEP have been slow. Part of the challenge is that PrEP is typically introduced into existing health systems through a hit-or-miss process that is rarely studied. We propose the Yunnan-ADARC HIV Prevention Program, an implementation science study of the process of introduction and implementation of PrEP in a specific international health system facing high rates of HIV incidence among men who have sex with men. YAHPP will introduce and evaluate the implementation of PrEP among over 1000 men who have sex with men, in eight municipalities in Yunnan, China utilizing tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) donated by Gilead Sciences. The study is guided by the Stages of Implementation Completion Framework (SIC) and will use SIC- associated assessment tools to measure progression across eight pre-defined stages of implementation, including documenting costs and required resources. YAHPP has two specific aims: 1) To evaluate whether the addition of Enhanced implementation strategies to Standard health system PrEP delivery improves client-services outcomes; 2) To compare the time, costs, and resources required for Standard versus Enhanced PrEP implementation. Enhanced PrEP implementation will rely on a centralized technical assistance strategy to deliver PrEP-related knowledge, skills, and best practices to clinics delivering PrEP. The outcome of the study will be an implementation blueprint that may be used across China and in other low- and middle-income countries to guide the introduction of PrEP into existing health systems.